Heretofore, transparencies or film positives were mounted between die cut pieces of cardboard for presentation purposes with the cardboard having die cut windows therein. The edges of the cardboard that define the window, would have to be blackened because the white fibers from the cut would be exposed. The transparency or positive would be taped in place to one of the cardboard pieces and both cardboard pieces would then have a tape extended around the periphery thereof. Photographers would present their work in this fashion. However, with time, the transparencies or positives would become damaged or scratched with repeated handling and usage.
In the art of laminating, in general, a mat quality is produced with a mat plate. The industry generally used either anodized aluminum or a nickel plate or sandblasted chrome plate, but nevertheless a plate that produced a mat quality. If a transparency were disposed between two plates the plates of this type would bend because the thickness of the transparency would causes stresses that would bend the two plates.
Heretofore there was no way to obtain a lamination having a flat appearing back. If the back of a normal piece of work that has been laminated is viewed, it appears very ripply. In conventional laminating, generally cardboard or rubber is used to give a sponginess to take up the thickness of the work. Whether cardboard or rubber is used, a softly undulating pattern is obtained which is quite evident when lamination of a transparency is attempted. The lamination would appear bumpy on the back. It was also assumed the transparency would melt at the usual lamination temperatures. Thus, those skilled in the art did not consider lamination of transparencies as being feasible because of the danger of melting the transparency and the inherent undulating or rippled effect on the back of the transparency. Accordingly, today when transparencies are viewed, other than a 35 mm which is viewed on a projector, in a portfolio presentation, they are between sheets of cardboard. As previously explained, problems arise with time in prior art cardboard mounted structures and damage of the transparencies result inasmuch as they are completely unprotected.